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Well, it seems that there are lots of orchids known the flower of which cannot possibly be used for fertilisation in that way. Some of the Cypripediums, for instance; there are no insects known that can possibly fertilise them, and some of them have never be found with seed." "But how do they form new plants?" "By runners and tubers, and that kind of outgrowth. That is easily explained.
In very many other cases, though there is no special mechanical contrivance to prevent the stigma receiving pollen from the same flower, yet, as Sprengel, and more recently Hildebrand and others have shown, and as I can confirm, either the anthers burst before the stigma is ready for fertilisation, or the stigma is ready before the pollen of that flower is ready, so that these so-named dichogamous plants have in fact separated sexes, and must habitually be crossed.
But what is sex but the difference between ovum and spermatozoon, between megagamete and microgamete? The theory then asserts that an individual developed from a cell formed by the union of male and female gametes is entirely incapable of producing female gametes again. Every zygote after conjugation or fertilisation may be said to be bisexual or hermaphrodite.
This theory, however, is still open to the objection that the female gametes before fertilisation, and half the male gametes, have the half quantity of sex-chromatin which by hypothesis determines the male condition, so that here again we have the male condition as something which is distinct from the characteristics of the spermatozoon. But if this is the case, what is the male condition?
I attended to the subject more or less during every subsequent summer; and my interest in it was greatly enhanced by having procured and read in November 1841, through the advice of Robert Brown, a copy of C.K. Sprengel's wonderful book, 'Das entdeckte Geheimniss der Natur. For some years before 1862 I had specially attended to the fertilisation of our British orchids; and it seemed to me the best plan to prepare as complete a treatise on this group of plants as well as I could, rather than to utilise the great mass of matter which I had slowly collected with respect to other plants.
Now if the physical conformation of the reproductive organs of the husband and the wife render this event possible or probable, then soluble suppositories and contraceptive douching are alike unreliable, by themselves or in combination. But if the two methods are combined, the chemical method and the mechanical method, then the protection against fertilisation may be regarded as almost absolute.
So long as they are just bright enough to catch the bee's eye a few yards away, they are certain to receive a visit in due season from that industrious and persistent commercial traveller. Having a circle of good customers upon whom they can depend with certainty for fertilisation, they have no need to waste any large proportion of their substance upon expensive advertisements or gaudy petals.
In very many other cases, though there be no special mechanical contrivance to prevent the stigma of a flower receiving its own pollen, yet, as C. C. Sprengel has shown, and as I can confirm, either the anthers burst before the stigma is ready for fertilisation, or the stigma is ready before the pollen of that flower is ready, so that these plants have in fact separated sexes, and must habitually be crossed.
It seems also that the flower itself is arranged and made attractive for the purpose of inviting this nuptial visit. I think I have been able to show that the nectary of the plant distils a sugary liquid which attracts the insects and obliges it to aid unconsciously in the work of direct or cross fertilisation. The last method of fertilisation is the more common.
We find the task of unravelling the writer's meaning rendered more difficult by a certain confusion in his use of terms, since fertilisation, i.e. syngamy the union of the different sex products seems to be confused with segmentation, i.e. germination; and this confusion is accentuated by the claim that "the main effect of the spermatozoon in inducing the development of the egg consists in an alteration in the surface of the latter which is apparently of the nature of a cytolysis of the cortical layer.
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